1. Field of the Invention:
The present invention relates to a tool breakage detecting apparatus for detecting breakage of a tool.
2. Description of the Prior Art:
In a conventional manner, prior to a machining operation on a workpiece, a tool is fed from a predetermined original position into contact with a reference block and this displacement amount of the tool is detected. Existence of tool breakage is detected depending upon whether this displacement amount is above a preset value. If existence of tool breakage is not detected, a plurality of machining operations are consecutively performed on a workpiece.
For this reason, it is impossible in the conventional manner to detect tool breakage prior to every machining operation and therefore it may happen that a workpiece will be machined by a broken tool and be damaged.
If tool breakage detection is performed by returning the tool to the original position after each machining operation, it is possible to detect tool breakage prior to every machining operation. However, this method has a disadvantage that the tool cycle time for machining operations becomes longer because of detection of tool breakage prior to every machining operation.